Totally agree about exercise affecting FT3. From my dose of NDT (1.5 grains) I get 15 hours of a normal day, then I fall asleep. I have no stamina to stay up late even to watch TV. For this reason, if I wake up at 5:00am I have to wait until 6:00am before I take my NDT otherwise my evening will end too early (8:00pm, and that's too early to go to bed). If I spend the day doing heavy duty gardening, same thing, fall asleep early because my T3 is all used up. Now, in the long run TSH will go higher to tell the system to make more or acquire more T3 (via T4) but, as is explained above, that's a long term effect.
You know, you can raise your own dose and get your own blood tests. It's a bit expensive initially but once you know where you are the expense drops off and you don't have to go begging to a doctor. You just need a doc for a prescription and then OK it runs out a bit earlier than they expect, but i don't think they have time to keep track of all that. I am in that situation and my Endo never asks why I run out early. If he did I would tell him that the dose I take makes me feel normal (never say "good" or "great", just say "normal").